I have wet sanded with 1500 and 2000. My process has been 1st step: Rotary - Meguiars Heavy cut wool pad w/M105 OR DA - Yellow (heavy cut) Chemical guys Hexlogic pad w/V32 followed by Da - Orange (med cut) Hexlogic pad w/V34 Da - White (polish) Hexlogic pad w/V36 Da - Black (finish) Hexlogic pad w/V38 after the whole process the paint looks great except for large deep scratches peppered throughout. there are no swirls or shallow scratches. V32 is rated to remove 1200-1500grit scratches so im convinced it is something with my technique (this is my first time buffing) So if yall were going to remove 2000 (1500 at worst) scratches how would you go about it? I feel as though I am not letting the compound work long enough but I don't want to burn through the paint. any tips welcome! thanks.
I have experimented using lighter pads and compound it results in deep AND shallow scratches left over. these scratches are all going the same direction so theyre not coming from the pads. they are for sure from my wetsand. I only used 1500 and 2000 though, so I am confused as to why they wont come out.
What machine are you using with the wool bonnet? You need high RPM resulting in heat for the "magic" to happen.
The scratches are probably from the wet sanding, getting some small pieces of dirt or dust under your sand paper.
My 67 Nova was painted by a friend about thirty years ago with PPG Delstar then cleared with Delglow, he roughed it in knowing there would be a lot of mechanical work to do so why get too fussy at that point, said it got as hard as a rock overnight, looked good, then..............................in about a month it started showing what you are experiencing, deep scratches. Not sure how long yours was left to cure but in my case I think it was from either filler rough-in sanding scratches or primer that was still trying to cure under the topcoat. I know so little about paint chemistry, maybe my ignorance is showing.
if the paint was a little soft you need to give it more time to dry OR use dish soap in the water when you wet sand look for build up on the paper and listen for the "squeak". when i am teaching someone to wet sand i can hear when the paper is clogged. . as far as going through, how much paint did you put on? when sanding, stay away from edges and squeegy often, the goal is to cut off just the high points to avoid going through. my rule for paint coats is: the best so far, i always spray four, three for the car and one for the floor
thanks for all the feedback! The paint is Eastwood brand 3:1 single stage urethane (orange) I put a lot of paint on knowing I would be wet sanding (5-6 coats) The paint has been on there for a month or so. I have a PC DA (using speed 1 to spread and speed 6 to buff) and a Eastwood Rotary (using 1800rpms as Meguiars suggests) I keep testing in a small 2x2 spot on the roof (with many scratches) using 3M paper. I use a little soap in my water and sure to check for dirt or loaded paper. when I sand the scratches cant be seen..(im sanding directionally to see when the previous grit scratches are out) Im using a flashlight to see if any deep scratches catch light and it always looks good. then as soon as I start compound they pop up again. (I use clean pads aswell) im struggling so hard to understand what is happening LOL *****I have experimented starting lower in the compound/pad aggressiveness like John suggested previously but I haven't started at the bottom and worked my way up... should I start with the black pad w/V38 and work backwards? would it make a difference?
Are you using quality sandpaper or China Chit? Soaking the paper for a while before and using dish soap as mention above helps as well.
Try buffing by hand with a soft cloth. Then use only a very small amount of your compound (try the finer stuff). Watch closely what is appearing. Don't worry about heavy cut right now (or IMO ever). Don't worry about a show finish right off the bat. You have to experiment to see if you are putting the scratches in it. Don't worry about the high gloss right now but try and find out why the scratches are "appearing".
One of the things I do is have two buckets of Luke warm water with a few drops of Dawn dish soap, in one bucket I soak my cut to size wet or dry paper let it soak. In the other bucket of water I use for sanding water. I wet down the area I'm going to sand and using a 3m squeegee made for this purpose, I squeegee all the water off the panel hopefully ridding the surface small contaminants that can get between your paper the paint, then re wet the panel and sand. Initial buffing [IMO] the 105 is not to aggressive for thirty day old urethane
How old is that 3M paper? I switched from 3M years ago to Japanese made papers because it appeared that the 3M grit was not uniform. Don't laugh but do you need to strain the sanding water? Cleanliness is critical including the work environment.
thanks for all the thoughts! yall are awesome. trying by hand is a good idea... I may try that tomorrow. I will also steal the "2 buckets" tip. the 3m paper was purchased about a month ago from wallyworld. so I tried to up the RPMs like Bandit Billy suggested and it seemed to work quite a bit better.. took out all the scratches but 2. I wonder if the Eastwood rotary isn't really accurate with its RPM settings and ive been trying to buff on too low of rpms??..... like I said..first shot at buffing so I wouldn't really notice the difference. got ran out by the mosquitos tonight but tomorrow I will do a full on test spot and report back.
I used 1500 and then 3000 wet and then 5000 wet on my DA to take out the scratches before I buffed. I was taught years ago to use lots of water, we used to keep a hose running on the area being sanded, messy but cuts down on problems. PPG Concept single stage buffed a couple of days after it was shot.
I've wet sanded paint applied by others, scary stuff since I have no idea how many coats of paint were applied. No matter how nice you wet sand, the scratches and orange peal in the primer always show after buffing. So IMO your paint is only as good as the surface of the last coat of primer Bob
Bob of course you are correct. If he can polish it up by hand and still see the scratches then it may tell him that it is in the primer coat and not from compounding. If it from compounding then he is going to have to adjust to overcome whatever compound/pad is causing him grief. I cannot imagine the paper doing that without knowing it. I can tell in an instant if there is something wrong with the paper as it glides across the surface(and some brands are pitful).
I was thinking they were from the primer aswell but I disproved this when I directionally sanded... ill sand 1500 one direction this way ////// then 2000 \\\\\ this way. the scratches are always diagonal indicating they are from the paper. My paper isn't gummed or dirty and use plenty of water... at this point im convinced its technique... what RPMs do you guys use for heavy cut wool pad? Maybe my rotary dial is inaccurate so ive been tryin to buff with too low of speeds.
Try some good paper. Go to an autobody supply store that sells professional quality products, Not Walmart.
^I was under the impression 3M was respected in the autobody industry and considered "quality" paper. Im using the "polish" specific line of 3M I mean the paint looks great to the naked eye...if you aren't LOOKING for defects but once I hit it with the flashlight the scratches can be seen. They are hard to get on camera but heres a little bit of what im dealin with. and heres what it looks like overall.
They are but like any other company they make varying qualities of product and you can guarantee Walmart buys the absolute cheapest.
What grit was the final for the primer? I used Slik Sand and a epoxy sealer and had some of the issues you have. not sure what grit I used as my final on the primers
At that stage I hate to say it, but id blame your primer. As stated, what was your last grit with it? Perhaps its scratches in the primer, or lack of fill from layers before. On the up side, what I can see of your paint and buff job, nobody that doesn't have their nose up against your car will notice anything wrong with it. My personal truck has issues that irritate the shit out of me (poor quality paint) but anyone who looks at it thinks its fine. Applying it you see every little thing wrong. step back, relax. Have a friend come look at it. I bet they don't see the scratches if you don't point them out
I cant remember what final grit I used for the primer it was so long ago. I used Eastwood Polyester Primer. I wanna say 320 or 400 then resanded the color with 600 after my first coat had about 743 runs from painting in low temps LOL (but hey, I learned and didn't do that again) BUT I think my problems have been solved. I just don't think my buffer RPMs are accurate. I finished the testing I started lastnight. Used V32 on Wool and cranked the RPMs to "2400-2800" and it took all but 2 scratches out. (the other scratches came out aswell after some light sanding) im thinking "2500" on my rotary is more like 2000 and that was giving me the false sense of "these scratches cant be taken out by a rotary" I finished wooling the roof and im happy with how its looking now. Waiting for my towels to dry and then im going to refine it with some foam on the DA I know people wouldn't notice the scratches if I didn't point em out but im using this car to learn so I figured id better work it out instead of saying "meh...its OK" But, this car was way jacked (garage fire) when I started so im overall pleased with how its going for my first ever body/paint/buff attempt. I don't expect it to be perfect (and its not) but if im not happy with it then why even bother, ya know?
As someone that has worked for 3M in the Collision Repair Industry for over 17 years, I can assure you the products they make and sell are the Industry standard. We not only make great products, we offer hands on training at the shop level. Nobody else in the industry has the field sale representation like 3M, which is why many in the business use our products. Also many of our products are called out by the O.E.M’s for aftermarket repairs.
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